Typically, weighing large items such as trucks including trailers, farm equipment and the like requires a relatively large platform in which at least one scale is positioned at the platform and weighs the vehicle. A problem with the common scale is that the exposure of an electronic receiving element to environmental hazards, for example moisture and chemical contact, as well as dust, ice, falling objects and weight impact. The common scale does not protect the load receiving element from external power sources such as lightning or welding ground leakage.
The present invention is designed to be self-centering which ensures that the load applied is not read inaccurately due to deflection by the mechanism being weighed. The invention is self dampening to check lateral forces with a minimum mechanical stress and is user friendly allowing for easy access for service. A low profile unit that allows for the lowest center of gravity possible and that has the same appearance and weighing integrity throughout the weight ranges from 2200 kg to 50,000 kg per weighing element. An electronic load receiving element of the present invention is totally enclosed in a moisture tight structure. The structure can be filled with a 20 grade non-detergent oil to a depth exceeding the load element depth to give a complete moisture seal. The mechanical structure housing the electronic load element is designed to resist impact equal to the shear strength of 2xc2xdxe2x80x3 foundation mounting bolts. Should the impact reach this breaking point the bolts would shear allowing the structure to dissipate the energy without significant damage to the electronic load element. The connection between the load receiving element and the load bearing platform is accomplished by inserting a phenolic cup between the surfaces. This acts as an insulator to protect the load receiving element against power sources coming from the load bearing platform. By utilising a ball and cup assembly the unit applies pressure from the load bearing surface to the electronic load receiving element in a vertical direction at all times. This remains constant even if the load bearing surface is subject to deflection. By using the specially designed load cup with the vertical dampening ring eliminates the necessity for bumper checks to resists lateral movement through 360 degrees. Using the radius design of the load cup supported by the ball is in itself a dampener. The more load applied the more resistance generated to resist lateral movement. The present invention requires no mechanical connection between the load bearing surface and the electronic load receiving element. This makes for easy access when maintenance is required. The complete elevation of 6.25xe2x80x3 for the largest units makes the present invention one of the lowest profile weighing components in the various size ranges. The present invention has the same appearance throughout the complete size range. The only noticeable change is in the physical size.
According to one aspect of the invention there is provided a housing for receiving a load cell comprising;
a base plate for receiving a load cell;
a weight dispersing means for use with the load cell so that a load is balanced;
an enclosure which surrounds the load cell therein from the base plate to the weight dispersing means;
and a receiving portion for receiving the load.
Preferably the enclosure has an outer wall which surrounds the cell, the outer wall extends generally vertically from the base plate.
Preferably the enclosure has an outer wall which surrounds the cell, the outer wall extends generally vertically from the base plate providing an area between the base plate and the weight dispersing means for enclosing the load cell therein, a cap is attached to a top end of the outer wall and has an opening located directly above the weight dispersing means which cap allows a top portion of the weight dispersing means to protrude from the enclosure so that the receiving portion can be attached thereto and wherein the cap has a guiding arrangement for limiting the movement of the weight dispersing means.
Preferably the weight dispersing means has a first receptacle mounted on the load cell, the receptacle is cylindrical in shape and has a vertical axis, a first side of the receptacle faces downward engaging the load cell, a second side opposite the first side faces upwardly, the second side has a concave center and an outer ledge located about the axis, wherein a second receptacle being cylindrical in shape has a second vertical axis which extends coaxially with the first vertical axis of the first receptacle, a first side of the second receptacle faces upwardly and a second side faces downward and has a concave center and an outer ledge located about the axis, and wherein a sphere is located between the each concave centers such that the center of the sphere is substantially located on the vertical axis, the sphere is arranged to move between each receptacle within each concave such that as a load is placed on the receiving portion downward force is applied to the sphere which balances the load within the enclosure by moving within each concave secured by each outer ledge.
Preferably the load cell is attached to a securing means which stabilizes the load cell within the enclosure, the enclosure has an outer wall which surrounds the cell, the outer wall extends generally vertically from the base plate in which the securing means engages, the securing means includes a ring plate in which the load cell is attached, the plate is placed onto the base plate within the enclosure and engages the outer wall.
Preferably a cover is placed on the enclosure so that the housing substantially resists elements such as water, dirt and the like, the cove.
Preferably a spark retarding material is located within the housing so that the load cell is surrounded by the material to prevent a spark emitted from the load cell to exit the housing.
Preferably the receiving portion has a disk which is mounted onto the weight dispersing means, the disk is arranged to fit within a sleeve located on a second disk, the sleeve has an insulating material in which the disk engages to prevent an electrical surge to damage the load cell.
One embodiment of the invention will now be described in conjunction with the accompanying drawings in which: